1. KEY CONCEPT Each population has a density, a dispersion, and a reproductive strategy.

2. Population density - number of individuals that live in a defined area.

3. Dispersion shows how individuals in a population are spaced.
Clumped
dispersion
Uniform
Random

4. There are three types of dispersion.
Clumped – Individuals clustered together
Occur when resources such as food or living space are clumped
Or because of social behavior

5. There are three types of dispersion.
Uniform (Even) – Individuals are separated by a fairly consistent distance
Result from social interactions resulting in individuals getting as far away from each other as possible
Ex: establishing territories x

6. There are three types of dispersion.
Random – Individual’s location is independent of the locations of other individuals
Usually results from seed dispersal by the wind or by birds

7. A survivorship curve is a diagram showing the number of surviving members over time from a measured set of births.

8. Survivorship curves can be type I, II or III.
Type I — low level of infant mortality and an older population
common to large mammals and humans
Type II — survivorship rate is equal at all stages of life
common to birds and reptiles
Type III — very high birth rate, very high infant mortality
common to invertebrates and plants

9. 14.4 Population Growth Patterns
KEY CONCEPT Populations grow in predictable patterns.

10. The size of a population is always changing.
14.4 Population Growth Patterns
The size of a population is always changing.
Four factors affect the size of a population.
Immigration
Emigration
Births
Deaths

11. Population growth is based on available resources.
14.4 Population Growth Patterns
Population growth is based on available resources.
Exponential growth is a rapid population increase due to an abundance of resources.

12. 14.4 Population Growth Patterns
Logistic growth is due to a population facing limited resources.

13. 14.4 Population Growth Patterns
Carrying capacity - maximum number of individuals in a population that the environment can support.
A population crash is a dramatic decline in the size of a population over a short period of time.

14. Ecological factors limit population growth.
14.4 Population Growth Patterns
Ecological factors limit population growth.
A limiting factor is something that keeps the size of a population down.

15. 14.4 Population Growth Patterns
Density-dependent limiting factors are affected by the number of individuals in a given area.
Predation
Competition
Resources (food)

16. 14.4 Population Growth Patterns
Density-independent limiting factors limit a population’s growth regardless of the density.
Unusual weather
Natural disasters
Human activities

17. 14.5 Ecological Succession
KEY CONCEPT Ecological succession is a process of change in the species that make up a community.

18. Succession regenerates or creates a community after a disturbance.
14.5 Ecological Succession
Succession regenerates or creates a community after a disturbance.

19. 14.5 Ecological Succession
There are two types of succession.
primary succession — started by pioneer species

20. 14.5 Ecological Succession
There are two types of succession.
2. secondary succession — started by remaining species